Water initially at 100 kPa and 25°C is compressed to 6 MPa and 25°C. Determine the change of enthalpy, in kJ/kg. Report your result to the nearst whole number using rounding. Assume that the density of the water is 997 kg/m3.

A piston - cylinder device contains 1 kg air at a pressure P = 125 kPa and T= 500K. Now, the gas is started to be heated at constant pressure until its temperature reaches to T = 600 K Calculate the amount of heat delivered to the system in kj during this quasi-equilibrium process. Hint : Air at these conditions can be treated as ideal gas. Answer:

The air in an automobile tire with a volume of 1.23 ft3 is at 72°F and 0.5 bar. Determine the amount of air that must be added to raise the pressure to the recommended value of 1 bar Assume the atmospheric to be 14.7 psia and the temperature and the volume to remain constant.

Nitrogen is isobarically expanded from 100 kPa and 600 K until the volume doubles in a closed piston-cylinder. Assume that specific heats are constant and evaluated at the average temperature. Hint: Nitrogen is an ideal gas.Determine the amount of heat transfer into the system, in kJ/kg? Calculate the change of enthalpy, in kJ/kg?Calculate the change of internal energy, in kJ/kg? Report your answer to the nearest whole number using rounding.